Flexible display panel and electro-optical apparatus

ABSTRACT

A first etching stop layer and an active layer are formed on an inner surface of a first glass substrate, and a second etching stop layer and a cover layer are formed on an inner surface of a second glass substrate. A display media is formed between the first glass substrate and the second glass substrate. A first passivation layer is formed on an outer surface of the second glass substrate. A first etching process is performed to expose the first etching stop layer. A first flexible substrate is formed on the exposed first etching stop layer, and a second passivation layer is formed on the first flexible substrate. The first passivation layer is removed. A second etching process is performed to expose the second etching stop layer. A second flexible substrate is formed on the exposed second etching stop layer, and the second passivation layer is removed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Divisional of and claims the priority benefit ofU.S. patent application Ser. No. 12/330,491, filed on Dec. 8, 2008, nowpending, which claims the priority benefits of Taiwan application SerialNo. 97132996, filed on Aug. 28, 2008. The entirety of each of theabove-mentioned patent applications is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display panel and a fabricatingmethod thereof, and an electro-optical device and a fabricating methodthereof. More particularly, the present invention relates to a flexibledisplay panel and a fabricating method thereof, and an electro-opticaldevice and a fabricating method thereof.

2. Description of Related Art

With development of technology, techniques for display devices aredeveloped accordingly, and flat panel displays (FPD) having features oflightness, slimness, shortness, and smallness gradually substituteconventional thick cathode ray tube (CRT) displays. Different types ofthe FPD such as a liquid crystal display (LCD), a plasma display panel(PDP), an electro luminescent display (ELD), and a vacuum fluorescentdisplay (VFD) generally include glass substrates. Since a whole weightof the FPD is determined by weight of the glass substrates, the weightand thickness of the glass substrates are managed to be reduced toobtain the FPD having a relative lightweight and thin thickness.

FIG. 1A to FIG. 1C are cross-sectional views illustrating a conventionalmethod of fabricating a display panel. Referring to FIG. 1A, the methodof fabricating the conventional display panel 1 can be described asfollows. First, a first glass substrate 10 and a second glass substrate20 are provided, and a thin film transistor layer 12 is formed on aninner surface 10 a of the first glass substrate 10, and a color filterlayer 22 is formed on an inner surface 20 a of the second glasssubstrate 20. Referring to FIG. 1B, a liquid crystal layer 30 is formedbetween the first glass substrate 10 and the second glass substrate 20and the first glass substrate 10 and the second glass substrate 20 areassembled. Referring to FIG. 1C, the first glass substrate 10 and thesecond glass substrate 20 are thinned to form a first thinned glasssubstrate 10′ and a second thinned glass substrate 20′.

The glass substrates are thinned must based on both of a grinding and apolishing process for reducing the weight and thickness of the glasssubstrates, so that a light and thin display panel 1 can be applied to adisplay device (not shown). The thickness of the first glass substrate10 and the second glass substrate 20 before the thinning is about 0.5mm, so that the first glass substrate 10 and the second glass substrate20 with the relatively great thickness have adequate compressivestrengths. However, to cope with a light and thin trend of the displays,the original thickness of the glass substrates are reduced, so that thethickness of the first glass substrate 10 and the second glass substrate20 is thinned from 0.5 mm to 0.3 mm. Now, the thinned glass substratesare liable to be cracked due to inadequate compressive strengthsthereof. Moreover, the first glass substrate 10 and the second glasssubstrate 20 are rigid substrates, so that but first thinned glasssubstrate 10′ and the second thinned glass substrate 20′ can reduce thewhole weight and thickness of the display device, the display devicestill cannot be bended to tolerate a specific degree of deformation, andaccordingly popularity of the display is influenced.

SUMMARY OF THE INVENTION

The present invention is directed to a flexible display panel, in whicha conventional glass substrate is substituted by a flexible substrate,so that a display applying the flexible display panel is bendable, andmay have a light and slim appearance.

The present invention is directed to a method for fabricating a flexibledisplay panel, by which the aforementioned flexible display panel can befabricated.

The present invention is directed to an electro-optical device havingthe aforementioned flexible display panel, which has a relatively lightand slim appearance.

The present invention is directed to a method for fabricating theaforementioned electro-optical device.

The present invention provides a method for fabricating a flexibledisplay panel. First, a first glass substrate and a second glasssubstrate are provided. Next, a first etching stop layer and an activelayer are sequentially formed on an inner surface of the first glasssubstrate, and a second etching stop layer and a cover layer aresequentially formed on an inner surface of the second glass substrate.Next, a display media is formed between the first glass substrate andthe second glass substrate and the first glass substrate and the secondglass substrate are assembled. Next, a first passivation layer is formedon an outer surface of the second glass substrate. Next, a first etchingprocess is performed to totally remove the first glass substrate andexpose the first etching stop layer. Next, a first flexible substrate isformed on the exposed first etching stop layer, and a second passivationlayer is formed on the first flexible substrate. Next, the firstpassivation layer on the outer surface of the second glass substrate isremoved. Next, a second etching process is performed to totally removethe second glass substrate and expose the second etching stop layer.Finally, a second flexible substrate is formed on the exposed secondetching stop layer, and the second passivation layer on the firstflexible substrate is removed.

The present invention provides a flexible display panel including afirst flexible substrate, a second flexible substrate and a displaymedia. A first etching stop layer and an active layer are disposed onthe first flexible substrate, wherein the material of the first etchingstop layer includes polyamide or silicon-rich dielectric material. Asecond etching stop layer and a cover layer are disposed on the secondflexible substrate, wherein the material of the second etching stoplayer includes polyamide or silicon-rich dielectric material. Thedisplay media is disposed between the first flexible substrate and thesecond flexible substrate.

The present invention provides a method for fabricating anelectro-optical device, which includes the aforementioned method forfabricating the flexible display panel.

The present invention provides an electro-optical device including theaforementioned flexible display panel.

In the present invention, since the flexible substrates are applied toserve as the substrates of the flexible display panel, compared to theconventional display panel applying rigid glass substrates, the flexibledisplay panel of the present invention can be bended to tolerate aspecific degree of deformation, and a display applying such displaypanel may have a light and slim appearance. Moreover, the presentinvention also provides the aforementioned method for fabricating theflexible display panel, and the electro-optical device applying theflexible display panel can also be bended, and has the light and slimappearance.

In order to make the aforementioned and other objects, features andadvantages of the present invention comprehensible, a preferredembodiment accompanied with figures is described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIGS. 1A to FIG. 1C are cross-sectional views illustrating aconventional method of fabricating a display panel.

FIG. 2 is a cross-sectional view of a flexible display panel accordingto an embodiment of the present invention.

FIG. 3A to FIG. 3J are cross-sectional views illustrating a method offabricating a flexible display panel of FIG. 2.

FIG. 4 is a schematic diagram illustrating an electro-optical deviceaccording to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 2 is a cross-sectional view of a flexible display panel accordingto an embodiment of the present invention. Referring to FIG. 2, in thepresent embodiment, the flexible display panel 100 includes a firstflexible substrate 110, a second flexible substrate 120 and a displaymedia 130, wherein the display media 130 is disposed between the firstflexible substrate 110 and the second flexible substrate 120.

In detail, a first etching stop layer 112 and an active layer 114 isdisposed on the first flexible substrate 110, and a second etching stoplayer 122 and a cover layer 124 are disposed on the second flexiblesubstrate 120. Particularly, the first etching stop layer 112 isdisposed between the active layer 114 and the first flexible substrate110, and the second etching stop layer 122 is disposed between the coverlayer 124 and the second flexible substrate 120. Moreover, the displaymedia 130 is disposed between the active layer 114 of the first flexiblesubstrate 110 and the cover layer 124 of the second flexible substrate120.

In the present embodiment, the first flexible substrate 110 and thesecond flexible substrate 120 include plastic substrates, metalsubstrate, glass having curvatures, or combinations thereof, so that theflexible display panel 100 can tolerate a specific degree ofdeformation. It should be noted that if the metal substrate is utilized,since the metal substrate is opaque, only one of the first flexiblesubstrate 110 and the second flexible substrate 120 of the flexibledisplay panel 100 can be the metal substrate. Namely, one of the firstflexible substrate 110 and the second flexible substrate 120 has to be atransparent substrate (such as the plastic substrate, the glass havingcurvature or a combination thereof), so that light can pass through theflexible display panel 100. Moreover, in other embodiments, at least oneof the first flexible substrate 110 and the second flexible substrate120 has to have functions of polarization, phase difference, brightnessenhancement, light delay, or at least two of the aforementionedfunctions. In other words, the first flexible substrate 110 and thesecond flexible substrate 120 not only have transparent and bendablefeatures, but also have functions of a general polarizer, a phase plate,a light delay film, and/or a brightness enhancement film, etc., andallocation of an extra polarizer, phase plate and/or brightnessenhancement film is unnecessary.

Moreover, the active layer 114 on the first flexible substrate 100 has aplurality of scan lines (not shown), a plurality of data lines (notshown), a plurality of thin film transistors (not shown), and aplurality of pixel electrodes (not shown). The thin film transistors areelectrically connected to the corresponding scan lines and data lines,and the pixel electrodes are electrically connected to the correspondingthin film transistors. Moreover, the type of the thin film transistorincludes a bottom gate type, a top gate type or other type, and thedoping type of the thin film transistor include N-type, P-type, or acombination thereof.

Moreover, a structure of the first etching stop layer 112 disposedbetween the active layer 114 and the first flexible substrate 110 is asingle layer structure or a multi layer structure, and the materialthereof includes polyamide or silicon-rich dielectric material. In thepresent embodiment, the silicon-rich dielectric material is preferablysilicon-rich silicon nitride (SixNy), and the so called silicon-richSixNy refers to that a proportion between silicon atoms and nitrideatoms of the SixNy is substantially 1-1.25, but the present invention isnot limited thereto, and the proportion between silicon atoms andnitride atoms of the SixNy is substantially greater than or equal to 1.In other embodiments, the silicon-rich dielectric material can besilicon-rich silicon oxide, silicon-rich silicon oxynitride,silicon-rich silicon carbide, silicon-rich silicon germanium,silicon-rich silicon arsenic, or other suitable materials, anddefinition of the silicon-rich is substantially the same to that of thesilicon-rich silicon nitride.

Moreover, material of the cover layer 124 on the second flexiblesubstrate 120 is determined according to the material of the displaymedia 130. If the material of the display media 130 is a photoelectricdeflection material such as liquid crystal material or other suitablematerials, the material of the cover layer 124 then can be a commonelectrode layer (not shown), a color filter layer (not shown), aplanarization layer (not shown), an alignment layer (not shown), or atleast two of the aforementioned layers. For example, if the cover layer124 has four material layers such as the common electrode layer, theplanarization layer, the alignment layer, and the color filter layer, adisposing method thereof can be described as follows. The planarizationlayer is disposed between the color filter layer and the commonelectrode layer, and the alignment layer covers the common electrodelayer, wherein the alignment layer can arrange liquid crystal moleculesalong a specific direction. Alternatively, the planarization layer isdisposed between the color filter layer and the common electrode layer,and the alignment layer covers the color filter layer, wherein thealignment layer can arrange liquid crystal molecules along a specificdirection. If the cover layer 124 has three material layers such as thecommon electrode layer, the alignment layer and the color filter layer,a disposing method thereof can be described as follows. The commonelectrode layer is disposed between the color filter layer and thealignment layer, and the alignment layer covers the common electrodelayer, wherein the alignment layer can arrange liquid crystal moleculesalong a specific direction. Alternatively, the color filter layer isdisposed between the common electrode layer and the alignment layer, andthe alignment layer covers the color filter layer, wherein the alignmentlayer can arrange liquid crystal molecules along a specific direction.If the cover layer 124 has other three material layers such as thealignment layer, the common electrode layer and the planarization layer,a disposing method thereof can be described as follows. The commonelectrode layer is disposed between the alignment layer and theplanarization layer, and the alignment layer covers the common electrodelayer, wherein the alignment layer can arrange liquid crystal moleculesalong a specific direction, and now the color light required fordisplaying color images can be provided by a light source (not shown) orthe color filter layer (not shown) can be disposed on the first flexiblesubstrate 110. If the cover layer 124 has two material layers such asthe common electrode layer and the alignment layer, the disposing methodis that the alignment layer covers the common electrode layer, whereinthe alignment layer can arrange liquid crystal molecules along aspecific direction, and now the color light required for displayingcolor images can be provided by the light source or the color filterlayer (not shown) can be disposed on the first flexible substrate 110.If the cover layer 124 has other two material layers such as the commonelectrode layer and the color filter layer, the disposing method is thatthe color filter layer then covers the common electrode layer, or thecommon electrode layer covers the color filter layer. If the cover layer124 has still other two material layers such as the planarization layerand the alignment layer, the disposing method is that the alignmentlayer covers the planarization layer, wherein the alignment layer canarrange liquid crystal molecules along a specific direction, and now thecolor light required for displaying color images can be provided by thelight source or the color filter layer can be disposed on the firstflexible substrate 110. If the cover layer 124 has further other twomaterial layers such as the planarization layer and the common electrodelayer, the disposing method is that the common electrode layer coversthe planarization layer, and now the color light required for displayingcolor images can be provided by the light source or the color filterlayer can be disposed on the first flexible substrate 110,alternatively, the planarization layer covers the common electrodelayer, and now the color light required for displaying color images canbe provided by the light source or the color filter layer can bedisposed on the first flexible substrate 110. In case the cover layerhas only one material layer, description of the disposing method is thenomitted. Moreover, material of the common electrode layer is for exampleindium tin oxide (ITO), indium zinc oxide (IZO), indium tin zinc oxide,hafnium oxide, zinc oxide, aluminium oxide, aluminium tin oxide,aluminium zinc oxide, cadmium tin oxide, cadmium zinc oxide, orcombinations thereof, but the present invention is not limited thereof.Material of the planarization layer can be an inorganic material (suchas silicon oxide, nitride oxide, silicon oxynitride, silicon carbide,hafnium oxide, aluminium oxide, or other materials, or combinationsthereof), organic material (such as photoresist, benzocyclobutene,cycloalkenes, polyimide, polyamide, polyester, polyol, oxypropylene,polystyrene, resin, polyether, polyketides, or other materials, orcombinations thereof), or a combination thereof. In other embodiments,if the display media 130 is a self-luminescent material, for example, anelectroluminescent material, the cover layer 124 can also be a drylayer, an oxygen-water blocking layer or an oxygen-water absorbinglayer.

Similarly, the second etching stop layer 122 disposed between the coverlayer 124 and the second flexible substrate 120 is a single layerstructure or a multi layer structure, and the material thereof includespolyamide or silicon-rich dielectric material. In the presentembodiment, the silicon-rich dielectric material is preferably thesilicon-rich silicon nitride (SixNy), but the present invention is notlimited thereto, and the so called silicon-rich SixNy refers to that aproportion between silicon atoms and nitride atoms of the SixNy issubstantially 1-1.25, but the present invention is not limited thereto.Namely, the proportion between silicon atoms and nitride atoms of theSixNy is substantially greater than or equal to 1. In other embodiments,the silicon-rich dielectric material can be silicon-rich silicon oxide,silicon-rich silicon oxynitride, silicon-rich silicon carbide,silicon-rich silicon germanium, silicon-rich silicon arsenic, or othersuitable materials, and definition of the silicon-rich is substantiallythe same to that of the silicon-rich silicon nitride. Moreover, in thepresent embodiment, preferably, the material of the first etching stoplayer 112 is substantially the same to the material of the secondetching stop layer 122, but the present invention is not limitedthereto, and in other embodiments, the material of the first etchingstop layer 112 is substantially different to the material of the secondetching stop layer 122.

Moreover, the material of the display media includes liquid crystalmaterial, electroluminescent material, or a combination thereof. If thedisplay media 130 of the flexible display panel 100 is the liquidcrystal, the flexible display panel 100 is referred to as liquid crystaldisplay (LCD) panel (such as a trasmissive display panel, atransflective display panel, a reflective display panel, a color filteron array display panel (COA), an array on color filter display panel(AOC), a vertical alignment (VA) display panel, an in-plane switching(IPS) display panel, a multi-domain vertical alignment (MVA), a twistnematic (TN) display panel, a super twist nematic (STN) display panel, apatterned-silt vertical alignment (PVA) display panel, a superpatterned-silt vertical alignment (S-PVA) display panel, an advancesuper view (ASV) display panel, a fringe field switching (FFS) displaypanel, a continuous pinwheel alignment (CPA) display panel, an axiallysymmetric aligned micro-cell mode (ASM) display panel, an opticalcompensation banded (OCB) display panel, a super in plane switching(S-IPS) display panel, an advanced super in plane switching (AS-IPS)display panel, an ultra-fringe field switching (UFFS) display panel, apolymer stabilized alignment (PSA) display panel, a dual-view displaypanel, a double screen display panel, a triple screen display panel, atriple-view display panel, a three-dimensional (3D) display panel, aelectrowetting display panel, or other types of display panels, orcombinations thereof), which is also referred to as non-self-luminescentdisplay panels. If the material of the display media 130 is theelectroluminescent material, the flexible display panel 100 is thenreferred as an electroluminescent display panel (for example, aphosphorescence electroluminescent display panel, a fluorescentelectroluminescent display panel or a combination thereof), which isalso referred to as a self-luminescent display panel, and theelectroluminescent material can be organic materials, inorganicmaterials, or a combination thereof. Moreover, molecules of theaforementioned materials include small molecules, polymer, or acombination thereof. If the display media 130 simultaneously includesthe liquid crystal and the electroluminescent material, the flexibledisplay panel 100 is then referred to as a hybrid display panel or asemi self-luminescent display panel.

Moreover, in the flexible display panel 100 of the present embodiment,preferably, adhesive layers 140 a and 140 b are respectively disposedbetween the first etching stop layer 112 and the active layer 114 andbetween the second etching stop layer 122 and the cover layer 124 forenhancing an adhesion between the first etching stop layer 112 and theactive layer 114, enhancing an adhesion between the second etching stoplayer 122 and the cover layer 124, and reducing a stress between theactive layer 114 and the first etching stop layer 112. The material ofthe adhesive layers 140 a and 140 b is a single-layer or a multi-layerdielectric material, and in the present embodiment, the silicon oxideand/or silicon oxynitride of the inorganic dielectric material is takenas an example, butt the present invention is not limited thereto, andother inorganic materials such as the material of the planarizationlayer, the organic dielectric materials such as the material of theplanarization layer, or combinations of the inorganic materials, orcombinations of the organic materials, or combinations thereof can alsobe applied. It should be noted that in another embodiment which is notillustrated, in the flexible display panel 100, the adhesive layer canbe selectively disposed at least one of between the first etching stooplayer 112 and the active layer 114 and between the second etching stoplayer 122 and the cover layer 124, or none adhesive layer is disposedbetween the first etching stoop layer 112 and the active layer 114, ornone adhesive layer is disposed between the second etching stop layer122 and the cover layer 124, which are all within the scope of thepresent invention.

In brief, in the present embodiment, the first flexible substrate 110and the second flexible substrate 120 are applied to serve as thesubstrates of the flexible display panel 100. Since the flexiblesubstrate is bendable, the flexible display panel 100 can tolerate aspecific degree of deformation. Compared to the conventional rigid glasssubstrates of the display panel 1 (referring to FIG. 1C), cracking ofthe flexible display panel 100 of the present embodiment due to pressurecan be avoided, and a display (not shown) applying such display panel100 may have a light and slim appearance.

The flexible display panel 100 can be fabricated according to afollowing method. In the following content, a structure of the flexibledisplay panel 100 of FIG. 2 is taken as an example, and the method offabricating the flexible display panel 100 is described in detail withreference of FIGS. 3A to FIG. 3J.

FIG. 3A to FIG. 3J are cross-sectional views illustrating a method offabricating a flexible display panel of FIG. 2. Referring to FIG. 3A,the method of fabricating the flexible display panel 100 can bedescribed as follows. First, a first glass substrate 110′ and a secondglass substrate 120′ are provided, wherein the first glass substrate110′ has an inner surface 110 a and an outer surface 110 b, and thesecond glass substrate 120′ has an inner surface 120 a and an outersurface 120 b.

Referring to FIG. 3B, the first etching stop layer 112, the adhesivelayer 140 a and the active layer 114 are sequentially formed on theinner surface 110 a of the first glass substrate 110′, and the secondetching stop layer 112, the adhesive layer 140 b and the cover layer 124are formed on the inner surface 120 a of the second glass substrate120′, wherein the adhesive layers 140 a and 140 b can respectivelyincrease the adhesion between the first etching stop layer 112 and theactive layer 114 and the adhesion between the second etching stop layer122 and the cover layer 124, and can respectively reduce the stressbetween the active layer 114 and the first etching stop layer 112 andthe stress between the second etching stop layer 122 and the cover layer124. It should be noted that in another embodiment, formation of atleast one of the adhesive layers 140 a and 140 b can be omitted. Namely,none adhesive layer is disposed between the first etching stop layer 112and the active layer 114 and between the second etching stop layer 122and the cover layer 124, or the adhesive layer is selectively disposedbetween the first etching stop layer 112 and the active layer 114 orbetween the second etching stop layer 122 and the cover layer 124.

In detail, at least one of the materials of the first etching stop layer112 and the second etching stop layer 122 includes silicon-richdielectric material or polyamide, and structures of the first etchingstop layer 112 and the second etching stoop layer 122 can be a singlelayer structure or a multi layer structure. For example, in the presentembodiment, the materials of the first etching stop layer 112 and thesecond etching stop layer 122 are for example, the silicon-richdielectric materials, and preferably the silicon-rich silicon nitride(SixNy), but the present invention is not limited thereto, wherein aproportion between silicon atoms and nitride atoms of the SixNy issubstantially 1-1.25, but the present invention is not limited thereto,and the proportion between silicon atoms and nitride atoms of the SixNyis substantially greater than or equal to 1. In other embodiments, thesilicon-rich dielectric material can be silicon-rich silicon oxide,silicon-rich silicon oxynitride, silicon-rich silicon carbide,silicon-rich silicon germanium, silicon-rich silicon arsenic, or othersuitable materials, and definition of the silicon-rich is substantiallythe same to that of the silicon-rich silicon nitride. Moreover, thematerials of the adhesive layers 140 a and 140 b, the active layer 114and the cover layer 124 are the same to that described in the embodimentof FIG. 2, and the structures of the active layer 114 and the coverlayer 124 are also the same to that described in the embodiment of FIG.2, and therefore, detailed description thereof is not repeated.

Referring to FIG. 3C, a display media 130 is formed between the firstglass substrate 110′ and the second glass substrate 120′ and the firstglass substrate 110′ and the second glass substrate 120′ are assembled.In the present embodiment, the display media 130 can be theself-luminescent material or the electroluminescent material, so thatthe material of the display media 130 is not limited by the presentinvention, and is just determined according to the type of the flexibledisplay panel 100 (referring to FIG. 2). The display media 130 is asthat described in the aforementioned content, and therefore detaileddescription thereof is not repeated.

Referring to FIG. 3D, a first passivation layer 126 is formed on theouter surface 120 b of the second glass substrate 120′, wherein thestructure of the first passivation layer 126 is the single layerstructure or the multi layer structure, and the material thereofincludes polyethylene, polypropylene, polycarbonate, polyethyleneterephathalate, polyether, or other suitable materials or combinationsthereof. Next, referring to FIG. 3E, a first etching process isperformed to totally remove the first glass substrate 110′ for exposingthe first etching stop layer 112.

In detail, in the present embodiment, the first etching process ispreferably performed under a room temperature below 26° C., and anetching rate of the first etching process is substantially 15-50 um/minfor example, but the present embodiment is not limited to thetemperature and/or the etching rate. During the first etching process,since the first passivation layer 126 is disposed on the outer surface120 b of the second glass substrate 120′, the second glass substrate120′ does not directly touches the etching fluid, so as to avoid beingeroded by the etching fluid. Since the first glass substrate 110′ has nopassivation layer, it is eroded by the etching fluid. When the etchingfluid reaches the first etching stop layer 112, the etching fluid isstopped by the first etching stop layer 112, and now the first glasssubstrate 110′ is totally removed by the etching fluid. Namely, thefirst glass substrate 110′ is dissolved in the etching fluid, which isnot that the first etching stop layer 112 is removed by the etchingfluid for exfoliating the first glass substrate 110′.

Moreover, in the present embodiment, the first etching process ispreferably multi etching steps including a first sub etching step and asecond sub etching step, wherein etching rate of the first sub etchingstep is substantially greater than that of the second sub etching step.Namely, most of the first glass substrate 110′ can be removed based onthe first sub etching step having the relatively fast etching rate, andthen the remained first glass substrate 110′ is removed based on the subsecond etching step having the relatively slow etching rate, so as toprevent the etching fluid excessively etching the etching stop layer112. In other words, based on the two sub etching steps having differentetching rates, an etching depth thereof can be accurately controlled. Inanother embodiment, only one sub etching step or another sub etchingstep can be performed between the first etching step and the secondetching step, or can be performed after the second etching step, and theetching rate of the other sub etching step is determined according to anactual requirement. Preferably, if the other sub etching step isperformed between the first etching step and the second etching step,the etching rate of the other sub etching step is between the etchingrate of the first etching step and the etching rate of the secondetching step. Alternatively, if the other sub etching step is performedafter the second etching step, the etching rate of the other sub etchingstep is substantially less than the etching rate of the second etchingstep, but the present invention is not limited thereto. Moreover, theother sub etching step can also be divided into multi sub etching steps.

Moreover, an etching selectivity between the first etching stop layer112 and the first glass substrate 110′ is preferably 20-25, but thepresent invention is not limited thereto, and the etching selectivitybetween the first etching stop layer 112 and the first glass substrate110′ is substantially greater than or equal to 20. For example, if thematerial of the first etching stop layer 112 is the silicon-rich siliconnitride, when the first glass substrate 110′ is etched by about 20 μm,the first etching stop layer 112 is only etched by about 1 μm. If thematerial of the first etching stop layer 112 is the polyamide, and whenthe first glass substrate 110′ is etched by about 25 μm, the firstetching stop layer 112 is only etched by about 1 μm.

Referring to FIG. 3F and FIG. 3G, the first flexible substrate 110 isformed on the exposed first etching stop layer 112, and a secondpassivation layer 116 is formed on the flexible substrate 110, wherein astructure of the second passivation layer 116 is the single layerstructure or the multi layer structure, and the material thereofincludes polyethylene, polypropylene, polycarbonate, polyethyleneterephathalate, polyether, or other suitable materials. Moreover, thematerial of the first flexible substrate 110 is as that described in theabove paragraph (the paragraph corresponding to FIG. 2), and thereforedetailed description thereof is not repeated.

Referring to FIG. 3H, the first passivation layer 126 on the outersurface 120 b of the second glass substrate 120′ is removed to exposethe second glass substrate 120′. Next, referring to FIG. 3I, a secondetching process is performed to totally remove the second glasssubstrate 120′ and expose the second etching stop layer 122.

In detail, the second etching process is preferably performed under aroom temperature below 26° C., and an etching rate of the second etchingprocess is substantially 15-50 um/min for example, but the presentembodiment is not limited to the temperature and/or the etching rate.During the second etching process, since the second passivation layer116 is disposed on the surface of the first flexible substrate 110, thefirst flexible substrate 110 does not directly touches the etchingfluid, so as to avoid being eroded by the etching fluid. Since the outersurface 120 b of the second glass substrate 120′ is not protected by thepassivation layer, it is eroded by the etching fluid. When the etchingfluid reaches the second etching stop layer 122, the etching fluid isstopped by the second etching stop layer 122, and now the second glasssubstrate 120′is totally removed by the etching fluid. Namely, thesecond glass substrate 120′ is dissolved in the etching fluid, which isnot that the second etching stop layer 122 is removed by the etchingfluid for exfoliating the second glass substrate 120′.

Moreover, in the present embodiment, the second etching process ispreferably the multi etching steps including a first sub etching stepand a second sub etching step, wherein etching rate of the first subetching step is substantially greater than that of the second subetching step. Namely, most of the second glass substrate 120′ can beremoved based on the first sub etching step having the relatively fastetching rate, and then the remained second glass substrate 120′ isremoved based on the second sub etching step having the relatively slowetching rate, so as to prevent the etching fluid excessively etching theetching stop layer 112. In other words, based on the two sub etchingsteps having different etching rates, an etching depth thereof can beaccurately controlled. In another embodiment, only one sub etching stepor another sub etching step can be performed between the first etchingstep and the second etching step, or can be performed after the secondetching step, and the etching rate of the other sub etching step isdetermined according to an actual requirement. Preferably, if the othersub etching step is performed between the first etching step and thesecond etching step, the etching rate of the other sub etching step isbetween the etching rate of the first etching step and the etching rateof the second etching step. Alternatively, if the other sub etching stepis performed after the second etching step, the etching rate of theother sub etching step is substantially less than the etching rate ofthe second etching step, but the present invention is not limitedthereto. Moreover, the other sub etching step can also be divided intomulti sub etching steps.

Moreover, an etching selectivity between the second etching stop layer122 and the second glass substrate 120′ is preferably 20-25, but thepresent invention is not limited thereto, and the etching selectivitybetween the second etching stop layer 122 and the second glass substrate120′ is substantially greater than or equal to 20. For example, if thematerial of the second etching stop layer 122 is the silicon-richsilicon nitride, when the second glass substrate 120′ is etched by about20 μm, the second etching stop layer 122 is only etched by about 1 μm.If the material of the first etching stop layer 112 is the polyamide,when the second glass substrate 120′ is etched by about 25 μm, thesecond etching stop layer 122 is only etched by about 1 μm. Moreover,the etching selectivity between the first etching stop layer 112 and thefirst glass substrate 110′ is substantially the same to that between thesecond etching stop layer 122 and the second glass substrate 120′, butthe present invention is not limited thereto, and the etchingselectivity between the first etching stop layer 112 and the first glasssubstrate 110′ can be substantially different to that between the secondetching stop layer 122 and the second glass substrate 120′. Moreover,the number of steps for etching the first glass substrate 110′ can bethe same or different to the number of steps for etching the secondglass substrate 120′.

It should be noted that in the present embodiment, the materials of thefirst etching stop layer 112 and the second etching stop layer 122 arepreferably the silicon-rich silicon nitride (SixNy), but the presentinvention is not limited thereto. A proportion between silicon atoms andnitride atoms of the SixNy is substantially 1-1.25, but the presentinvention is not limited thereto, and the proportion between siliconatoms and nitride atoms of the SixNy is substantially greater than orequal to 1. The etching selectivity respectively between the firstetching stop layer 112 and the first glass substrate 110′ (referring toFIG. 3D) and between the second etching stop layer 122 and the secondglass substrate 120′ are substantially 20-25, but the present inventionis not limited thereto, and the etching selectivity respectively betweenthe first etching stop layer 112 and the first glass substrate 110′ andbetween the second etching stop layer 122 and the second glass substrate120′ are substantially greater than or equal to 20.

TABLE 1 Experiment condition 1 2 3 4 Flux of silicon- 0.15 0.33 0.5 1contained gas/ flux of nitride- contained gas Etching selectivity 5.118.68 16.05 24.69

In detail, in the table 1, the etching selectivity respectively betweenthe first etching stop layer 112 and the first glass substrate 110′(referring to FIG. 3D) and between the second etching stop layer 122 andthe second glass substrate 120′ are listed, and the experiment data ofthe flux of silicon-contained gas/the flux of nitride-contained gas ofthe silicon-rich silicon nitride used for generating the first etchingstop layer 112 and the second etching stop layer 122. Thesilicon-contained gas includes silane, silicon ethane, di-silane,di-silane ethane, tetramethylsilane, or other suitable gases, orcombinations thereof, and the nitride-contained gas includes nitrogen,ammonia, laughing gas, nitrous oxide, nitric oxide, nitrogen dioxide, orother suitable gases, or combinations thereof. In the presentembodiment, the silicon-contained gas and the nitride-contained gas arerespectively silane and ammonia, but the present invention is notlimited thereto. According to the table one, when the flux of thesilicon-contained gas/the flux of the nitride-contained gas of thesilicon nitride used for generating the first etching stop layer 112 andthe second etching stop layer 122 are respectively 1, 0.5, 0.33, and0.15, the corresponding etching selectivity for the first glasssubstrate 110′ and the second glass substrate 120′ are about 25, 16, 9,and 5 respectively. Namely, the smaller the flux of thesilicon-contained gas/the flux of the nitride-contained gas of thesilicon nitride of the first etching stop layer 112 and the secondetching stop layer 122 is, the smaller the corresponding etchingselectivity for the first glass substrate 110′ and the second glasssubstrate 120′ is, and the weaker the capability for stopping theetching fluid is. Moreover, the etching fluid of the present embodimentincludes hydrofluoric acid, acetic acid, hydrochloride acid, phosphaticacid, nitric acid, sulfuric acid, or other suitable etching fluid orcombinations of at least two of the above acids. In the presentembodiment, the etching fluid is hydrofluoric acid, but the presentinvention is not limited thereto.

Referring to FIG. 3J, the second flexible substrate 120 is formed on thesurface of the exposed second etching stop layer 122, and the secondpassivation layer 116 on the first flexible substrate 110 is removed,wherein the material of the second flexible substrate 110 is the same tothat described in the embodiment of FIG. 2, so that detailed descriptionthereof is not repeated. Now, fabricating of the flexible display panel100 is approximately completed.

In brief, according to the fabricating method of the flexible displaypanel 100, the first glass substrate 110′ and the second glass substrate120′ are assembled, and the display media 130 is formed between thefirst and second glass substrates 110′ and 120′, and then the firstglass substrate 110′ and the second glass substrate 120′ are removedaccording to the first etching process and the second etching process,so as to form the first flexible substrate 110 and the second flexiblesubstrate 120. Since the glass substrate belongs to the rigid substrate,poor alignment accuracy of the layers of the flexible display panel 100can be avoided. Moreover, since the flexible substrate is bendable, thefabricated flexible display panel 100 can tolerate a certain degree ofdeformation. Compared to the conventional display panel 1 applying therigid glass as the substrate, cracking of the flexible display panel 100of the present embodiment due to pressure can be avoided, and a display(not shown) applying such display panel 100 may have a light and slimappearance.

FIG. 4 is a schematic diagram illustrating an electro-optical deviceaccording to an embodiment of the present invention. Referring to FIG.4, the flexible display panel 100 can be electrically connected to anelectronic device to form the electro-optical device 200. A method offabricating the electro-optical device 200 includes the method offabricating the flexible display panel 100 and processes of fabricatingvarious electro-optical devices 200, and by assembling the obtaineddisplay, the electro-optical device 200 is obtained. Since the flexibledisplay panel 100 applies the flexible substrates as the substratesthereof, besides the feature of bendable, the electro-optical devices200 applying the flexible display panel 100 also has advantages of lightand slim.

Moreover, the electronic device 210 can be a control device, anoperation device, a processing device, an input device, a memory device,a driving device, a luminescent device, a protection device, a sensingdevice, a detecting device, or other functional devices, or combinationsthereof. The electro-optical device 200 can be a portable product (suchas a mobile phone, a video camera, a camera, a laptop computer, a gamemachine, a watch, a music player, an e-mail transceiver, a mapnavigator, a digital picture, or other similar products), a video-audioproduct (such as a video-audio player or similar products), a screen, atelevision, a board, a panel within a projector, a panel withinautomated teller machine (ATM), or other suitable products.

In summary, since the flexible substrates are applied to serve as thesubstrates of the flexible display panel, the flexible display panel ofthe present invention can tolerate a certain degree of deformation.Compared to the conventional display panel applying the rigid glass asthe substrate, cracking of the flexible display panel of the presentembodiment due to pressure can be avoided, and the display applying suchdisplay panel may have a light and slim appearance. Moreover, thepresent invention also provides a method of fabricating the flexibledisplay panel, by which the glass substrates are combined via thedisplay media, and then the glass substrates are removed based onetching processes, so as to form the flexible substrates. Based on suchfabricating method, the poor alignment accuracy problem can be avoided.Moreover, the electro-optical device applying such flexible displaypanel can also be bended, and has the light and slim appearance.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

1. A flexible display panel, comprising: a first flexible substrate,having a first etching stop layer and an active layer disposed thereon,wherein the material of the first etching stop layer comprises polyamideor silicon-rich dielectric material; a second flexible substrate, havinga second etching stop layer and a cover layer disposed thereon, whereinthe material of the second etching stop layer comprises polyamide orsilicon-rich dielectric material; and a display media, disposed betweenthe first flexible substrate and the second flexible substrate.
 2. Theflexible display panel of claim 1, wherein at least one of the firstflexible substrate and the second flexible substrate comprise plasticsubstrates, metal substrates, glass having curvatures, or combinationsof at least two of the above substrates.
 3. The flexible display panelof claim 1, wherein at least one of the first flexible substrate and thesecond flexible substrate have functions of polarization, phasedifference, brightness enhancement, light delay, or at least two of theabove functions.
 4. The flexible display panel of claim 1, wherein anadhesive layer is disposed at least one of between the first etchingstop layer and the active layer and between the second etching stoplayer and the cover layer.
 5. An electro-optical device, comprising aflexible display panel of claim 1.